update diesel to 2.1.0 and diesel-async to 0.3.0 (issue #2882) (#2895)
* update diesel to 2.1.0 and diesel-async to 0.3.0 (issue #2882)
* get rid of deprecated RawValue type alias usage, explicitly import diesel types instead of using wildcard import
* Update diesel-derive-enum and diesel-derive-newtype libraries
* Revert manual changes to schema.rs
* Update to newer diesel-cli image in CI, run fix-clippy before schema comparison, update schema to one generated with diesel-cli 2.1.0 and clippyfixed